The invention relates to an air filter for a ventilation device of a motor vehicle. The invention furthermore relates to an arrangement of such an air filter in a flow area of such a ventilation device.
It can be gleaned as known from DE 10 2005 048 841 B3 to insert an air filter having a planar, drawer-like or cassette-like extension along its extension direction or transversely relative to a flow direction into a flow area of the ventilation device. Here, the air filter comprises a filter medium arranged along its planar extension, the filter medium being bordered, in the present case, peripherally by a frame wall. In this instance, several sections are taken out of the frame wall, which are able to be brought into engagement with guide elements in the form of guiding pins of the ventilation device in order to guide the air filter when it is inserted into the flow area.
The guiding pins thus push through the filter housing and therefore require an elaborate design of the air filter. In order to additionally obtain a sufficient guide length, it is necessary for respective guide domes to adjoin the corresponding sections of the filter housing, the guide domes being able to receive the guiding pins. This also requires a more elaborate design of the air filter.
The object of the present invention is therefore to create an air filter, as well as an arrangement of the type referred to at the beginning, which enables as reliable and yet as simple a guiding as possible of the air filter when it is inserted into the receiving shaft.
In order to create an air filter of the type referred to at the beginning which enables, in as reliable and yet as simple a manner as possible, an appropriate guiding option for introducing the air filter in the receiving shaft, or for removing it therefrom, provision is made according to the invention for the section to be designed as a notch on an edge of the frame wall and to be formed with an undercut relative to the edge, whereby the air filter is able to be braced transversely relative to the insertion direction when being inserted in two directions. As a consequence, provision is made according to the invention for the at least one section to be designed to open out towards an edge on an outer side or a broad side of the frame wall of the air filter. Such a section that opens out towards the edge of the frame wall is conventionally known as a notch. This notch may be introduced into the frame wall by cutting, as well as by molding, casting or by way of another method, or may be provided on the frame wall in another way.
With this notch, it is possible to have corresponding guide elements run on sides of the receiving shaft, for example over a considerable portion of or the entire length along the filter, without the air filter here having to be pushed through by a guide element, for example a guide rail. The guide rail can therefore run substantially on the outer side, for example the broad side, of the filter housing, such that, for example, no extra recesses have to be provided within the filter medium. This enables a simple design of the air filter by only one or a plurality of notches having to be provided. In addition, a particularly favorable guiding option hereby arises since, as explained above, the corresponding guide element can extend in a simple manner on sides of the ventilation device over the complete length of the air filter.
Here, the notch is formed with an undercut relative to the edge of the frame wall, such that the air filter is able to be braced transversely or perpendicularly relative to the insertion direction when being inserted in the two spatial directions. The notch is thereby formed in such a way that a movement of the air filter can be achieved substantially in only the insertion direction or the extraction direction.
A particularly simple and yet easy-to-guide air filter can be achieved by the notch and therefore the corresponding guide element on sides of the ventilation device also having an angular shape or a T-shape in their cross-section.
As an alternative to this, it is in particular also conceivable to form the notch as a narrow slot having a wide bay in the region that is separated from the edge. Such a section that has, for example, been configured in the manner of a keyhole, also enables a good and smooth guiding of the air filter.
In a further embodiment of the invention, several sections are arranged congruently in the insertion direction, whereby they are able to be brought into engagement with a single guide element during insertion. The guide element on sides of the ventilation device can therefore, for example, be designed as a linearly-running guide rail which is configured with corresponding simplicity and along which a smooth guiding of the air filter can be achieved.
An embodiment in which the filter medium is designed as a folded filter fleece and is fastened to the frame walls at least in certain regions is furthermore advantageous. Fastening in certain regions is particularly conceivable because separate frame walls are only formed in the region transverse to the folding and the further frame walls are themselves able to be formed by the folded filter fleece.
Finally, it has been shown to be advantageous if respective bent edges of a fold of the filter medium are aligned in the insertion direction. There hereby arises a correspondingly inherently rigid filter medium that is robust during insertion.
The advantages referred to above in connection with the air filter according to the invention therefore apply the same way for the arrangement.
Further advantages, features and details of the invention arise from the following description of a preferred exemplary embodiment as well as with the aid of the drawings.